Discussion of Background
U.S. Pat. No. 5,856,653 describes a heating container that includes a recess which can accommodate a tube containing a cosmetic product. The container is arranged so as to impart a slow heating action by transference of the heat emitted by the container through the walls of the tube to the cosmetic product contained therein. The container can be used to heat and possibly re-fluidize residues of product that have dried on the tube walls, thereby rendering them re-usable for a fresh application of the cosmetic product.
U.S. Pat. No. 5,775,344 describes an arrangement having a tube containing a cosmetic product in which the walls of the tube directly incorporate a means of heating arranged so as to heat the product contained in the tube by conduction. The means of heating the tube wall performs the same function as the external heating container. In effect, it enables product residues dried onto the internal walls of tube to be re-fluidized, thereby rendering them re-usable for a fresh application of the cosmetic product.
According to the teachings of the art, it is known that a product held in a container can be heated in order to recover residues of the product that have dried onto the internal walls of the container. In this manner, the entire product is heated. To use the product, a quantity of the heated product is taken up by means of an applicator. The product is therefore applied hot, which can impart useful cosmetic properties to the product, for example, by improving the curl of the eyelashes to which it is applied.
In order to raise the temperature of the quantity of product taken up sufficiently to confer these desired cosmetic properties, it is necessary to heat the entirety of the product. This technique poses a problem associated with premature aging of the product not being used for a given application, and when this product is used in subsequent applications, it will have been re-heated numerous times. Aging can cause deterioration of the cosmetic properties of the product, for example, volatilization of the solvents contained in the product formulation. Moreover, as the product is being heated, temperature gradients form inside the device, and the quantity of product taken up can also have this temperature gradient or be inconsistent as a result of this gradient, resulting in uneven deposition of make-up during a given application.
There is thus a need to heat the quantity of product applied at the time of use and in a uniform manner without requiring heating of all of the product in the container. To this end, the current state of the art involves a two-step procedure. In the first step, a quantity of product is applied at ambient temperature, and in the second step the applied product is then heated by means of a known device such as that described in document FR-A-2,743,991.